Find the exact value of cos^ -1((cos(4pi/3))?

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Find the exact value of cos^ -1((cos(4pi/3))?

Find the exact value of cos^ -1((cos(4pi/3))

2007-09-04 20:19:54 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics

3 answers

cos 4pi/3 = 1/2

cos^-1 (1/2) = pi/3

2007-09-04 20:26:37 · answer #1 · answered by forgetfulpcspice 3 · 0⤊ 1⤋

Cos 4pi

2016-12-24 19:24:21 · answer #2 · answered by ? 4 · 0⤊ 0⤋

arccos[cos(4π/3)] = arccos(-1/2) = 2π/3

Unless otherwise specified, the inverse trig functions return only the reference value.

In the book "Precalculus with Unit Circle Trigonometry" by David Cohen, on Page 519 we find the following definition of the inverse cosine function.

cos¯¹(x) is the (unique) number in the interval [0, π] whose cosine is x.

2007-09-04 21:03:25 · answer #3 · answered by Northstar 7 · 0⤊ 0⤋